Journal Article

FZJ-2025-05590

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Comparing QCD+QED via full simulation versus the RM123 method: U-spin window contribution to $${a}_{\mu }^{\text{HVP}}$$

Altherr, A. ; Campos, I. ; Cotellucci, A.FZJ* ; Gruber, R. ; Harris, T. ; Komijani, J. ; Margari, F. ; Marinkovic, M. K. ; Parato, L. ; Patella, A. ; Rosso, S. ; Tantalo, N. ; Tavella, P. (Corresponding author)

2025
Springer Heidelberg

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Please use a persistent id in citations: doi:10.1007/JHEP10(2025)158  doi:10.34734/FZJ-2025-05590

Abstract: Electromagnetic corrections to hadronic vacuum polarization contribute significantly to the uncertainty of the Standard Model prediction of the muon anomaly, which poses conceptual and numerical challenges for ab initio lattice determinations. In this study, we compute the non-singlet contribution from intermediate Euclidean current separations in quantum chromo- and electrodynamics (QCD+QED) using $C^{\star}$ boundary conditions in two ways: either non-perturbatively by sampling the joint probability distribution directly or by perturbatively expanding from an isospin-symmetric theory. This allows us to compare the predictions and their uncertainties at a fixed lattice spacing and volume, including fully the sea quarks effects in both cases. Treating carefully the uncertainty due to tuning to the same renormalized theory with $N_{\text{f}}= 1 + 2 + 1$ quarks, albeit with unphysical masses, we find it advantageous to simulate the full QCD+QED distribution given a fixed number of samples. This study lays the ground-work for further applications of $C^{\star}$ boundary conditions to study QCD+QED at the physical point, essential for the next generation of precision tests of the Standard Model.

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Contributing Institute(s):

1. Jülich Supercomputing Center (JSC)

Research Program(s):

1. 5111 - Domain-Specific Simulation & Data Life Cycle Labs (SDLs) and Research Groups (POF4-511) (POF4-511)
2. GRK 2575 - GRK 2575: Überdenken der Quantenfeldtheorie (417533893) (417533893)

Appears in the scientific report 2025

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Database coverage:
; ; ; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; DOAJ Seal ; Ebsco Academic Search ; Essential Science Indicators ; IF >= 5 ; JCR ; National-Konsortium ; SCOAP3 sponsored Journal ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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